This invention relates to novel couplers for use in hair coloring compositions comprising one or more oxidative hair coloring agents in combination with one or more oxidizing agents. The invention also relates to hair coloring compositions of these novel couplers and to coloring or dyeing of hair using compositions containing these couplers.
Coloration of hair is a procedure practiced from antiquity employing a variety of means. In modern times, the most extensively used method employed to color hair is to color hair by an oxidative dyeing process employing hair coloring systems utilizing one or more oxidative hair coloring agents in combination with one or more oxidizing agents.
Most commonly a peroxy oxidizing agent is used in combination with one or more oxidative hair coloring agents, generally small molecules capable of diffusing into hair and comprising one or more primary intermediates and one or more couplers. In this procedure, a peroxide material, such as hydrogen peroxide, is employed to activate the small molecules of primary intermediates so that they react with couplers to form larger sized compounds in the hair shaft to color the hair in a variety of shades and colors.
A wide variety of primary intermediates and couplers have been employed in such oxidative hair coloring systems and compositions. Among the primary intermediates employed there may be mentioned p-phenylenediamine, p-toluenediamine, p-aminophenol, 4-amino-3-methylphenol, and as couplers there may be mentioned resorcinol, 2-methylresorcinol, 3-aminophenol, and 5-amino-2-methylphenol. A majority of the shades have been produced with dyes based on p-phenylenediamine.
Recently, 2-(4,5-diamino-1H-pyrazol-1-yl)ethanol has been extensively used for providing fashionable red coloration. This primary intermediate couples with conventional couplers to produce a coloration ranging from orange to red. Due to the limitation of color range derived from the pyrazole, there is need to develop a coupler or couplers to generate blue coloration.
This invention provides novel couplers of the formula (1): 
wherein X is selected from halogen and R5SO4 where the halogen is preferably Cl, Br or I; R, R1, and R2 are each individually selected from C1 to C22 alkyl and C1 to C22 mono or dihydroxyalkyl, or two of R, R1 and R2 together with the nitrogen atom to which they are attached form a C3 to C6, preferably C4 to C6, saturated or unsaturated ring optionally containing in the ring one or more additional hetero atoms selected from O, S and N atoms; R3 and R4 are each individually selected from C1 to C6 alkyl, C1 to C6 hydroxyalkyl, C1 to C6 alkoxy, C1 to C6 aminoalkyl or R3 and R4 together form a C2 to C5 alkylene group; and R5 is selected from C1 to C22 alkyl and C1 to C22 mono or dihydroxyalkyl. Preferably X is Cl, Br, I and R5SO4 where R5 is C1 to C4 alkyl, more preferably methyl; and preferably R, R1, R2, R3 and R4 are each individually C1 to C3 alkyl, and more preferably methyl.
These novel couplers are used to provide coloration to hair in which there is good dye uptake by the hair and provides shades or colors which are stable over a relatively long period of time. The novel couplers provide for dyeing of hair to impart color or shades that possess good wash fastness, good selectivity and do not undergo significant changes on exposure to light, perspiration or shampooing.
The coupler compounds of this invention are those of formula (1): 
wherein X is selected from halogen and R5SO4 where the halogen is preferably Cl, Br or I; R, R1, and R2 are each individually selected from C1 to C22 alkyl and C1 to C22 mono or dihydroxyalkyl, or two of R, R1 and R2 together with the nitrogen atom to which they are attached form a C3 to C6, preferably C4 to C6, saturated or unsaturated ring optionally containing in the ring one or more additional hetero atoms selected from O, S and N atoms; R3 and R4 are each individually selected from C1 to C6 alkyl, C1 to C6 hydroxyalkyl, C1 to C6 alkoxy, C1 to C6 aminoalkyl or R3 and R4 together form a C2 to C5 alkylene group; and R5 is selected from C1 to C22 alkyl and C1 to C22 mono or dihydroxyalkyl. Preferably X is Cl, Br, I and R5SO4 where R5 is C1 to C4 alkyl, more preferably methyl; and preferably R, R1, R2, R3 and R4 are each individually C1 to C3 alkyl, and more preferably methyl.
Preferably X is selected from Cl, Br I and R5SO4 where R5 is C1 to C3 alkyl, preferably a methyl group; R, R1, and R2 are each individually selected from a C1 to C3 alkyl group, preferably methyl groups; a piperazinium or imidazolium group and R3 and R4 are individually selected from C1 to C3 alkyl groups, preferably methyl groups.
Especially preferred couplers of this invention are the following compounds: [2-(3-dimethylamino-phenoxy)-ethyl]-trimethyl-ammonium; bromide; 1-[2-(3-dimethylamino-phenoxy)-ethyl]-1,4-dimethyl-piperazin-1-ium; bromide; and 1-[2-(3-dimethylamino-phenoxy)-ethyl]-3-methyl-3H-imidazol-1-ium; bromide.
The novel coupler compounds of formula (1) of this invention are readily prepared according to the following reaction sequence where X, R, R1, R2, R3, R4 and R5 are as defined hereinbefore: 
In this synthesis an aminophenol (2) is reacted with a 2-haloethanol, such as 2-bromoethanol, in the presence of potassium carbonate in dimethylformarnide to produce the alcohol compound (3). Transformation of this alcohol compound (3) into a compound (4) is carried out by treatment of the alcohol compound with triphenylphosphine and a halo-succinimide, such as bromosuccinimide (NBS). Treatment of compound (4) with a quaternization reagent (NRR1R2) produces a compounds of formula (1) of this invention.